Engine



Jan. 17, 196

J. C. HENNING ETAL ENGINE Filed Marbh 16, 1959 2 Sheets-Sheet 1 Fial iINVENTOR C.H enni.n d ChaflesA.L.Ruh1

ATTORNEYS Jan. 17, 1961 J, c, HENNlNG T 2,968,252

ENGINE Filed March 16, 9

2 Sheets-Sheet 2 V YINIVENTOR James Cflenning d. Chafle s A.L.Ruh1

grywslw ATTORNEYS United States Patent ENGINE James C. Henning andCharles A. L. Ruhl, Kalamazoo,

Mich., assignors to The New York Air Brake Company, a corporation of NewJersey Filed Mar. 16, 1959, Ser. No. 799,738

2 Claims. (Cl. 103-136) This invention relates to rotary engines of thevane type, and particularly to engines of this type employingsemi-balanced vanes which are biased outward into sealing engagementwith the cam ring by fluid pressure. The term engine is used herein inits generic sense and it will be understood that it includes pumps aswell as motors.

In these engines, of which the one described in Rosen Patent 2,393,223,granted January 15, 1946, is typical, the outer end of each vane is inengagement with the cam ring along two spaced lines of contact whichextend between the port plates disposed on opposite sides of the rotor.Formed in the outer end of each vane between these lines of contact is abalance chamber whose opposite ends open through the side faces of thevane and communicate with the high and low pressure ports in the portplates as the vane passes by those ports. Each of these chambers is incontinuous communication with the space in the vane slot beneath theinner end of its vane by passages formed in the side faces of the vane.The port plates are also provided with vane ports which are incommunication with the high and low pressure manifolds of the engine andwhich are arranged to transmit high pressure fluid to the inner end ofeach vane slot when that vane is crossing the high pressure port, and tovent each slot when that vane is crossing the low pressure port. Thehigh and low pressure ports are in more restricted communication withthe manifolds than the vane ports and, as a result, the balance chamberand the inner end of each vane develop net forces on the vane that urgeit outward against the cam ring in the region of the high pressure portand urge it inward in the region of the low pressure port.

In eneral, this method of controlling the vanes is satisfactory becauseit provides a large sealing force in the region where leakage or blow-byacross the outer ends of the vanes is most apt to occur, and reduces thesealing force and thus decreases wear on the cam ring in that regionwhere the leakage problem is not as acute. However, in low speedengines, i.e., those operating at about 700 r.p.m., the centrifugalforces acting on the vanes are so small that the pressure bias forcingthe vanes inward in the region of the low pressure port tends to causethe vanes and the cam ring to separate. Vanes which separate from thecam ring in the low pressure region will return to it with a suddenimpact when their slots are again connected with the high pressuremanifold. This hammering causes objectionable noise and greatly reducesthe life of the cam ring.

The object of this invention is to provide an improved engine of thetype mentioned which is capable of operating at low speeds without riskof causing separation between the vanes and the cam ring. According tothe invention, the spaces in the vane slots beneath the vanes are incontinuous communication with the high pressure manifold, and thebalance chambers and the connecting passages between these chambers andthe vane slots are so located that they are never in free communication2,968,252 Patented Jan. 17, 196] with the low pressure port in the portplate. Because of this arrangement, the pressures acting in the vaneslots and in the balance chambers are always equal and are always high.The area of each balance chamber, projected on plane normal to thelongitudinal axis of the vane, is less than the effective area of theinner end of the vane and is so selected that the high pressure fluidacting on these areas produces a net biasing force on the vanesufiicient to maintain it in sealing contact with the cam ring withoutcausing undue wear of this ring. Since the bias on the vanes is alwaysin an outward direction, low speed operation, with its attendant smallcentrifugal forces, will not cause hammering of the vanes on the camring.

The preferred embodiment of the invention will now be described indetail with reference to the accompanying drawing, in which:

Fig. l is an axial sectional view of a vane pump incorporating theinvention.

Fig. 2 is a sectional view taken on line 22 of Fig. 1.

Fig. 3 is a sectional view taken on line 33 of Fig. 1 showing therelationship between the surface of the cam ring and the inlet anddischarge ports.

Fig. 4 is a view of the front face of one of the port plates.

1Fig. 5 is a view of the front face of the other port p ate.

Fig. 6 is an enlarged view of a portion of Fig. 3 showing the spatialrelationship between one of the balance chambers and one of the inletports.

Fig. 7 is a sectional view taken on line 77 of Fig. 6.

As shown in the drawings, the pump comprises a housing having separablesections 11 and 12 which are joined by four bolts and which are bored toreceive and hold a pumping cartridge 13. Inlet and discharge ports 14and 15 are formed in housing sections 11 and 12, respectively, andcommunicate with cored inlet and discharge manifolds 16 and 17 whichencircle drive shaft 18. The shaft is supported in housing sections 11and 12 by bearings 19 and 21, respectively, and in one of the portplates by hearing 22.

The cartridge 13 comprises two substantially identical port plates 23and 24, cam ring 25, and rotor 26. The unit is held together by twobolts 27 whose heads are received in counterbores formed in port plate23 and which are threaded into tapped holes formed in port plate 24. Therotor 26 is connected in driven relation with shaft 18 by splines 28 andis formed with a plurality of uniformly spaced radial slots 29 whichreceive the laminated sliding vanes 31. The inner ends of these slotsare enlarged, as shown, to provide vane-biasing chambers 32 adjacent theinner ends of the vanes. The outer peripheral edges of the rotor arebeveled at 33 to provide access between the ports in port plates 23 and24 and the inter-vane working chambers.

As shown in Figs. 2 and 4, port plate 23 is formed with twodiametrically opposed teardrop-shaped inlet 3' ports 34 and 35 whichopen through the front face of the plate and communicate with the radialslots 36 and 37, respectively. When the pump is assembled, these slotsopen into the longitudinal extensions 38 and 39 of inlet manifold 16that are formed in housing section 12. Port plate 23 also contains twodiametrically opposed arcuate discharge ports 41 and 42 which arelocated 48, 49, 51 and 52; the plug 49 also serving as a socket forlocating pin 53. These plugs are required in order to preventcommunication between the inlet and discharge manifolds through theinter-vane'working chambers. Port plate 24 is-provided with the sameports and passages as port plate 23 but in this plate the bores 43",44', 46 and 47 are not plugged but communicate with discharge manifold17.

The cam ring 25 is conventional, employingfour constant radius sectionsA, B, C and D separated by transition zones, as shown in Fig. 3; theradius of sections A and B, being equal, and the radius of sections CandDbeing equal. Fig. 3 also shows the annular relationship between thesurface of the cam ring and the ports in plate 23 when the cartridge isassembled.

The vanes 31 are of the laminated type disclosed in the Rosen patentmentioned previously. The two lami-, naeare free to move relatively toeachother so that the outer end of each vane is always in engagementwith the cam ring along two spaced lines of contact (see-Fig. 6 in whichthe'points 54 and 55irepresent end views of these lines). The outeredges of the 'two laminae of each vane are chamfered, asshown in'Figs. 3and 6, to define a balance chamber 56 which is located between the linesof contact with cam ring25 and ,whose cross-sectional area, projected ona plane normal to'the longitudinal axis of the vane, is less than thecrosssectional area of the inner end of the vane. pumping cartridge isassembled, the inner margins of chambers 56 are located radially outwardof the outer margins of inlet ports 34, 34', 35 and 35. Each of thesebalance chambers communicates with the vanebiasing chamber 32 beneathits vaneviaa passage 57 that is defined by grooves formed in the mating.faces of the laminae.

When drive shaft 18 is rotated in the direction of the arrow in Fig. 3,fluid is drawn into the inter-vane working chambers through inlet port14, inlet manifold 16, manifold extensions 38 and 39, radial passages36, 36, 37 and 37' and inlet ports 34, 34, 35 and- 35', and isdischarged under high pressure through discharge ports 41 and 42, bores43 and 44', discharge manifold 17, and discharge port 15. The highpressure prevailing in discharge manifold 17 is transmitted continuouslyto the vane-biasing chambers 32 through bores 46 and 47 and annulargroove 45 where it acts upon the inner ends of vanes 31 and urges themoutward into sealing engagement with cam ring 25. Since the passages 57define closed high pressure conduits between chambers 32 and 56, andsince the running seals between the side faces of the vanes and thefront faces of the port plates and between the outer ends of the vanesand the cam' ring (along lines 54 and 55) isolate the chambers 56- fromthe inlet ports 34, 34', 35 and 35' and from the intervane workingchambers, the high pressure in manifold 17 and biasing chambers 32 willalso exist in balancechambers 56. The fluid pressure in the' balancechambers produces forces which urge the vanes in an inward direction,but since the cross-sectional area of these chambers is less than thecross-sectional area of the biasing chambers, the net force exerted oneach vane acts in an outward direction. The ratio of the area of chamber32 to the area of chamber 56 is so selected that the When the e netbiasingforce is large enough to hold the vanes 31 in contact with camring 25 at the operating speed of the pump, but not so large as to causeundue wear of the cam ring.

As stated previously, the drawings and descrpition relate only to apreferred embodiment of the invention. Since many changes canbe made inthe structure of this embodiment without departing from the inventiveconcept, the following claims should provide the sole measure of thescope of the invention.

What is claimed is:

1. In a rotary engine of the vane type including a rotor having aplurality of vaneslots spaced around its periphery, a vane reciprocablein each slot, the opposite side faces of each vane being in sliding andsealing engagement with two spaced parallel walls and the outer end ofeach vane being in sliding contact with a cam ring along two spacedlines which extend between the said two parallel walls, and at least onehigh and one-low pressure port formed in one ofsaidwalls; theimprovement which comprises a balance chamber formed in the outer end ofeach vane betweenithe spacedlines of contact, the chambers and the lowpressure port being so located relatively to each other that they areisolated from one another at all times by the lines of contact and bythe running seals between the walls and the opposite side faces of thevanes; means forming a continuously open flow path between the highpressure port and the spaces in the vane slots beneath the vanes; andmeans defining a closed conduit connecting the space beneath each vanewith the balance chamber at the outer end of that vane.

2. In a rotary engine of the vane type including a rotor having aplurality of vane slots spaced around its periphery, a vane reciprocablein each slot, the opposite side faces of each vane being in sliding andsealing engagement with two spaced parallel walls and the outer end ofeach vane being in sliding contact with a cam ring along two spacedlines which extend between the said two parallel walls, and at least onehigh and low pressure port formed in one of said walls, the improvementwhich comprises a balance chamber formed'in the outer end of each vanebetween the spaced lines of contact and opening through the side facesof the vane, the innermargin of each chamber being located radiallyoutward of the outer margin of the low pressure port; a closed passageconnecting each balance chamber with the space in the vane slot beneathits vane; and means forming a continuously open flow path between thehigh pressure port and the spacesin. the vane slotsbeneath the vanes.

References Cited in the file of this patent UNITEDSTATES PATENTS1,573,683 Ditfinger Feb. 16, 1926 2,423,271 Talbot July 1, 19472,786,422 Rosaen et al. Mar. 26, 1957 2,809,595 Adams et all Oct. 15,1957 2,832 293 Adams et al. Apr. 29, 1958 2,839,007 Benedek- June 17,1958 FOREIGN PATENTS.

568,518 Great Britain Apr. 9, 1945

